I would never buy a product that doesn't do what you want based on the assumption that it will become what you want.
What if they have trouble getting the dev-c++ version working and it takes months or worse they decide not to bother because there is hardly any demand?

I think there is plenty of demand. Besides, you are not buying a programming language. You are buying an SDK, Software Development Kit.
Typically, they try to get support going for many different compilers in today's world. You can't have just one compiler anymore. Different compilers meet different needs. I got more use out of Visual C++ 6 than I did with C++.net. When it came time to choose a new IDE, I went with Dev-C++. I find it does a better job for what I want. While it's true that some people will find more use out of Visual C++.net than they will with Dev-C++, I think Dev-C++ does a better job because it is using a clean version of C++. Microsoft usually tries to define their own standard of how a language should be and that doesn't always work out for them(Woooo). Visual C++.net 2003 does a better job of getting closer to the standard, I think it is still tainted.

Which brings me to my closing point...

If Mike and Ravey says they are going to do something, they will. Have you been reading Mike's journal and the post I just put up? He just answered that he has been working the bugs out and getting it ready.
Besides, I highly doubt that it will too much work to get it to work. You can already compile Direct X 9 programs in Dev-C++.
SoulMan